JP5201643B2 - Undercut processing mechanism - Google Patents

Abstract

The invention is an undercut processing mechanism that is able to perform de-molding easily even when the undercut portion (P1) of a molding (P) has a shape that is irregular on both sides of the direction orthogonal to the direction of de-molding by implementing a larger movement stroke within a limited set-up space. Inside a holder (30) that is disposed inside a movable mold (13), a pair of molding cores (51, 52) that mold the undercut portion (P1) are connected to and supported by a holding piece (40) that moves in the de-molding direction. During de-molding, the respective molding cores (51, 52) are guided by guiding means (33, 34) from a molding position in which the cores contact each other towards a mold release position in which the cores are separated, and each moves in front or in back so as to move past each other in opposite directions from one end of the holding piece (40) to the other end.

Description

  The present invention relates to an undercut processing mechanism that molds a molded product having an undercut portion with a fixed die and a movable die, and makes the undercut portion ready for die cutting.

  Conventionally, as this type of mold apparatus, for example, a loose core ejector apparatus described in Patent Document 1 is known. That is, it is locked to a mold core that forms the inner surface of the molded product, a movable loose core support rod that penetrates the core and is inclined with respect to the core surface, a movable mold plate, and a pedestal plate. And a slide base disposed in the slide path of the ejector plate so as to be slidable relative to the guide means rod, and the loose core support rod is interlocked with the movement of the slide base. .

  In such a loose core ejector device, one end of the guide means rod is locked to a holder that is tightly fitted in a recess formed in the lower surface of the movable side template, and the loose core support rod is attached to the core. An insertion hole formed at substantially the same inclination angle as the guide means rod is slidably inserted, and this insertion hole has the only structure for setting the inclination angle of the loose core support rod.

JP 2002-326233 A

  However, in the conventional technology as described above, not only the loose core support rod but also the guide means rod are inclined, and the mechanism for moving each rod at the same inclination angle is an ejector plate and a movable side type. It is comprised so that it may disperse | distribute to a board. Therefore, a large installation space is required compared to the amount of movement of the piece with the undercut part shape necessary for die-cutting of the undercut part of the molded product. There was a problem that it was difficult to reduce costs.

  In addition, the undercut portion can be dealt with only in one direction of the outside or inside of the molded product. For example, the undercut portion protruding to the inside of the lower surface of the molded product is on both sides intersecting the die cutting direction. In the case where the shape is uneven, it has been impossible to punch out such a molded product. Therefore, in addition to the shape of the undercut portion in the moldable molded product, there is a problem that the position and number are limited to a very narrow range.

  In particular, the more complicated the shape of the undercut portion, the larger the moving stroke of the piece with the undercut portion shape necessary for die cutting. In order to cope with such a problem, a device for realizing a large moving stroke within a limited installation space has been desired.

  The present invention has been made paying attention to the problems of the prior art as described above, can be configured compactly, can meet the demand for space saving, and can be processed and incorporated into a mold. In particular, even if the undercut part of the molded product has an uneven shape on both sides that intersect the die-cutting direction, a larger moving stroke can be achieved within a limited installation space. An object of the present invention is to provide an undercut processing mechanism that can be realized and easily punched.

The gist of the present invention for achieving the object described above resides in the inventions of the following items.
[1] A mold (11) for molding a molded product (P) having an undercut portion (P1) with a fixed die (12) and a movable die (13), and the undercut portion (P1) can be die-cut. In the undercut processing mechanism to be in a state,
A single holder (30) provided in the fixed mold (12) or the movable mold (13);
A pair of molded cores (51, 52) which are housed in the holder (30) and are molded in a state of surrounding the undercut portion (P1) from both sides intersecting the die cutting direction;
A holding piece (40) housed in the holder (30) and movable in a die-cutting direction;
Each of the molded cores (51, 52) is slidably connected to both sides of the base piece side with respect to the holding piece (40) so as to cross the die cutting direction and escape from the undercut part (P1). A molding position that contacts each other so as to surround the undercut portion (P1) from both sides in the holder (30), and a separation position that protrudes outside the holder (30) and is separated from the undercut portion (P1). It can be moved to each mold position,
In the holder (30), as the holding piece (40) moves, the molding cores (51, 52) are simultaneously moved from the molding position toward the mold release position in the die-cutting direction and both side directions, respectively. A pair of symmetrically extending guide means (33, 34) for guiding along the direction,
Each of the molding cores (51, 52) is provided such that at least the base end side overlaps with the holding piece (40) in the front-rear direction, and when moving from the molding position to the mold release position, the base end side is provided. Is an undercut processing mechanism characterized in that the holding piece (40) passes back and forth in the opposite direction from one end side to the other end side.

[2] Out of the molded cores (51, 52), either the outer wall of one molded core (51) or the inner wall of the holder (30) with which the outer wall of the one molded core (51) is in sliding contact. A first oblique groove (33) extending in the inclined direction in which the one molding core (51) moves is provided, and the other one is also extended in the inclined direction and slides on the first oblique groove (33). A first oblique line (57) that can be fitted is provided, and the first oblique groove (33) or the first oblique line (57) in the holder (30) is connected to the guide means (33, 34). One of the
Of the molded cores (51, 52), either the outer wall of another molded core (52) or the inner wall of the holder (30) with which the outer wall of the other molded core (52) is in sliding contact A second oblique groove (34) extending in the inclined direction in which the molding core (52) moves is provided, and extends in the inclined direction and is slidably fitted into the second oblique groove (34) on either one of them. And a second oblique groove (34) or a second oblique groove (58) in the holder (30) is connected to the other of the guide means (33, 34). The undercut processing mechanism according to [1], wherein the undercut processing mechanism is performed.

[3] It has an ejector pin (20) that is driven in the die-cutting direction and operates to protrude.
The ejector pin (20) is disposed at a position where the tip side faces the holder (30), and the tip side is integrally connected to the holding piece (40) [1] or [ The undercut processing mechanism according to 2].

  [4] [1], [2] or [4], wherein a tip end side for molding the undercut portion (P1) of the molding cores (51, 52) is detachably assembled as a separate body. 3]. The undercut processing mechanism according to [3].

  [5] [1], [2], [3] or [5], wherein each of the molded cores (51, 52) is set to a length corresponding to a die cutting stroke of the molded product (P). 4]. The undercut processing mechanism according to [4].

  [6] The holder (30) is configured as a part of the mold itself surrounding the hollow part (13a) provided in the movable mold (13) provided with the holder (30) or the fixed mold (12). The undercut processing mechanism according to [1], [2], [3], [4] or [5], which is characterized.

The present invention operates as follows.
According to the undercut processing mechanism described in [1] above, a pair for forming the undercut portion (P1) in a single holder (30) provided in the fixed mold (12) or the movable mold (13). The molding cores (51, 52) and the holding pieces (40) for driving the molding cores (51, 52) are accommodated. Here, the holder (30), the holding piece (40), and the molding cores (51, 52) can be configured as one unit.

  In this way, the molded cores (51, 52) are not dispersed in the ejector base plate (15) or the movable mold (13), and the fixed mold (12) or the movable mold (13) can be connected via the holder (30). It can be concentrated on either one of them. Accordingly, a compact configuration can be achieved, a demand for space saving can be met, and processing and incorporation into the mold (11) are facilitated. Furthermore, the overall structure can be simplified, and the manufacturing cost can be greatly reduced.

  When molding the molded product (P), the molding cores (51, 52) in the holder (30) are in contact with each other so as to surround the undercut portion (P1) of the molded product (P) from both sides. Is supported by the holding piece (40). At the time of die cutting after molding, each molding core (51, 52) connected to the holding piece (40) is moved to the holder (30) as the holding piece (40) moves in the die cutting direction. It protrudes outside and moves to a mold release position separated from the undercut part (P1).

  At this time, the respective molding cores (51, 52) are guided to the mold release position while being guided by the guide means (33, 34) in the holder (30) in the die-cutting direction and the inclined direction moving simultaneously in both directions. Moving. Here, the guide means (33, 34) corresponding to the respective molding cores (51, 52) extend separately in the inclined directions that are symmetrical to each other in order to separate the respective molding cores (51, 52) in both side directions. Yes.

  In addition, each molded core (51, 52) is provided such that at least the base end side overlaps with the holding piece (40) in the front and rear directions, and these base end sides are in both directions with respect to the holding piece (40). It is slidably connected. When the molding cores (51, 52) move from the molding position to the mold release position, the base end sides of the molding cores (51, 52) pass from one end side to the other end side of the holding piece (40) in the opposite directions. Move to.

  As a result, each molded core (51, 52) can be stored compactly in the holder (30) in a state where it does not spread too much sideways, but a larger moving stroke is ensured during die cutting. be able to. Therefore, even if the undercut portion (P1) protruding inside the lower surface of the molded product (P) has a large unevenness on both sides intersecting the die-cutting direction, the undercut portion (P1) can be removed without difficulty. Thus, the entire molded product (P) can be easily punched out.

  According to the undercut processing mechanism described in [2], the one molding core (51) moves in an inclined direction in which either the outer wall of one molding core (51) or the inner wall of the holder (30) moves. A first oblique groove (33) extending is provided, and a first oblique groove (57) that extends in the same inclination direction and is slidably fitted into the first oblique groove (33) is provided on either one of the holders. The first oblique groove (33) or the first oblique line (57) in (30) is one of the guide means (33, 34).

  Also, a second oblique groove (34) extending in an inclined direction in which the other molded core (52) moves is provided on either one of the outer wall of the other molded core (52) and the inner wall of the holder (30). On the other hand, a second oblique groove (58) that extends in the inclined direction and is slidably fitted into the second oblique groove (34) is provided, and the second oblique groove (34) in the holder (30) is provided. Alternatively, the second oblique line (58) is the other of the guide means (33, 34).

  Thereby, the movement of each molding core (51, 52) is reliably and smoothly guided by the fitting relationship between the groove and the strip provided in the holder (30) and the load at the time of die cutting. Since it is dispersed without concentrating on one place, durability is enhanced. In addition, since high accuracy at the time of design is eased, further cost reduction is possible.

  According to the undercut processing mechanism described in [3] above, the ejector pin (20) that is driven in the die-cutting direction and protrudes is provided. The front end side of the ejector pin (20) is arranged so as to face the inside of the holder (30), and the holding piece (40) is integrally connected to the front end side. Therefore, the holding piece (40) in the holder (30) can be reliably moved in the mold release direction according to the ejecting operation of the ejector pin (20).

  According to the undercut processing mechanism described in [4] above, the front end side for molding the undercut portion (P1) of each molded core (51, 52) is detachably assembled as a separate body. Thereby, the part which shape | molds an undercut part (P1) can be changed later to another type, and versatility spreads.

  According to the undercut processing mechanism described in [5] above, each molding core (51, 52) is set to a length corresponding to the punching stroke of the molded product (P). Thereby, it can respond | correspond suitably from the big stroke in a die cutting of a molded article (P) to a small stroke.

  According to the undercut processing mechanism described in [6] above, the holder (30) itself is configured as a movable mold (13) or a fixed mold (12) provided with the holder (30). That is, a hollow portion (13a) serving as a substitute for the internal space of the holder (30) is directly formed in the mold (11), and the holding piece (40) and the molding cores (51, 52) are formed in the hollow portion (13a). ) Can be stored movably. This eliminates the need for parts of the holder (30) itself, reduces the number of parts, simplifies the configuration of the entire apparatus, and further reduces costs.

According to the undercut processing mechanism according to the present invention, even when the undercut portion of the molded product has an uneven shape on both sides intersecting the die cutting direction, a larger moving stroke can be realized in a limited installation space. It can be easily punched.
Moreover, it can be configured compactly, can meet the demands for space saving, can be easily processed and assembled into the mold, and the configuration is simple, so it does not take time and effort to assemble. Cost reduction can be realized.

It is a longitudinal cross-sectional view which shows the state at the time of shaping | molding of the metal mold | die of the molding die apparatus which concerns on embodiment of this invention, and an undercut process mechanism. It is a longitudinal cross-sectional view which shows the state at the time of the die cutting of the metal mold | die and undercut process mechanism of the metal mold apparatus which concerns on embodiment of this invention. It is a longitudinal cross-sectional view which shows the state at the time of shaping | molding of the metal mold | die of the molding die apparatus which concerns on embodiment of this invention, and an undercut process mechanism from another direction. It is a perspective view which shows the holder of the undercut process mechanism which concerns on embodiment of this invention. It is a front view which shows the inner side of the two divided parts which comprise the holder of the undercut process mechanism which concerns on embodiment of this invention. It is a perspective view which shows the mode in the holder at the time of die cutting of the undercut process mechanism which concerns on embodiment of this invention. It is a perspective view which shows the state which attached the one shaping | molding core to the holding piece of the undercut processing mechanism which concerns on embodiment of this invention. It is a perspective view which shows the positional relationship of a holding | maintenance piece and a pair of shaping | molding core at the time of shaping | molding of the undercut process mechanism which concerns on embodiment of this invention. It is a perspective view which shows the positional relationship of a holding | maintenance piece and a pair of shaping | molding core at the time of die cutting of the undercut process mechanism which concerns on embodiment of this invention. It is explanatory drawing which shows the movement stroke of a pair of shaping | molding core at the time of shaping | molding of the undercut process mechanism which concerns on embodiment of this invention, and die-cutting. It is explanatory drawing which shows the movement stroke of a pair of shaping | molding core at the time of shaping | molding of the conventional undercut process mechanism, and a die cutting. It is a perspective view which expands and shows the principal part of the molded article shape | molded by the undercut process mechanism which concerns on embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment that represents the present invention will be described based on the drawings.
1 to 3 are longitudinal sectional views for explaining the operation of the mold 11 and the undercut processing mechanism constituting the molding die apparatus 10 according to the present embodiment. FIG. 1 shows a state during molding of the molded product P, and FIG. 2 shows a state during die cutting of the molded product P. FIG. 3 is a longitudinal sectional view as seen from another direction perpendicular to the plane of FIG. 1 showing the state of the molded product P during molding.

  The molding die apparatus 10 is an apparatus that molds the molded product P with the mold 11. As shown in FIG. 12 and FIGS. 1 to 3, the molded product P according to the present embodiment has a bumper shape that extends in the longitudinal direction as a whole, and a clip-like underside at predetermined intervals inside the lower surface thereof. A cut portion P1 is provided. The undercut portion P1 has a concavo-convex shape projecting so as to hang down from the inside of the lower surface of the molded product P and projecting on both sides. The material of the molded product P is not limited to a synthetic resin such as plastic, but may be a metal such as iron, copper, or aluminum.

  As shown in FIGS. 1 and 2, the mold 11 of the molding die apparatus 10 molds the fixed mold 12 that molds the outer surface side of the molded product P and the inner surface side including the undercut portion P1 of the molded product P. And a movable mold 13. A movable mounting plate 14 is installed below the movable mold 13, and an ejector base plate 15 made of a double-layered plate material can be driven in the vertical direction between the movable mold 13 and the movable mounting plate 14. It is arranged.

  The undercut processing mechanism that forms the basis of the present invention enables the undercut portion P1 to be released when the molded product P is released. Such an undercut processing mechanism includes an ejector pin 20 that is driven in a die-cutting direction to perform a protrusion operation, a holder 30 provided in the movable die 13, and is housed in the holder 30, and the undercut portion P <b> 1 is die-cut. A pair of molding cores 51 and 52 molded in a state of being enclosed from both sides intersecting with the direction, a holding piece 40 which is also housed in the holder 30 and is movable in the die-cutting direction, and the like.

  As shown in FIGS. 1 and 2, the ejector pin 20 is made of a round bar member, and is erected on the ejector base plate 15 in a vertical state. A base end portion 22 of the ejector pin 20 is integrally fixed to the ejector base plate 15 via a knock pin 23. As the ejector base plate 15 moves upward, the ejector pin 20 is driven in the die-cutting direction to project. The ejector pin 20 is disposed at a position where its tip 21 faces the inside of the holder 30, and the tip 21 is inserted into the holder 30.

  The holder 30 is integrally provided in the movable mold 13. Here, the movable mold 13 is previously formed with a hollow portion 13a for installing the holder 30, and the holder 30 is embedded in the hollow portion 13a and closed with a separate lower plate 13b. . A vertical hole 13c through which the ejector pin 20 passes is formed in the lower plate 13b. A block 13d that prevents the holder 30 from coming out of the hollow portion 13a is attached to the lower end side of the holder 30.

  As shown in FIGS. 4 and 5, the holder 30 is formed by combining two piece parts 30 a having the same shape, and is formed in a box-like cylindrical shape having an internal space 31 having an open upper end surface and a lower end surface. Yes. Tapers 32 are provided on the inner walls on both sides of the upper end opening of the holder 30 to slide a pair of molded cores 51 and 52, which will be described later, obliquely upward. Further, guide means for movably guiding the respective molding cores 51 and 52 are provided on the inner wall of each piece 30a, which will be described later.

  As shown in FIGS. 1 and 2, a distal end portion 21 of the ejector pin 20 is movably inserted in a lower portion of an internal space 31 of the holder 30, and a holding piece 40 is integrated with the distal end portion 21. It is connected. Here, the holding piece 40 is driven in the mold release direction as the ejector pin 20 moves up and down, and is slidable between the molding position shown in FIG. 1 and the mold release position shown in FIG. It is stored in the internal space 31.

  As shown in FIGS. 6 to 9, the holding piece 40 is composed of the illustrated rectangular parallelepiped member, and the tip end portion 21 of the ejector pin 20 is screwed to the lower end side thereof (see FIG. 1). On the upper end surface of the holding piece 40, there is provided a protrusion 41 that intersects at right angles to the die-cutting direction that is the axial direction of the ejector pin 20 and extends in both directions to escape from the undercut portion P1. Formed cores 51 and 52, which will be described below, are connected to the protrusion 41 so as to be movable along both sides.

  As shown in FIGS. 6 to 9, the respective molding cores 51 and 52 are made of the members having the same shape as illustrated, and are connected on the holding piece 40 so as to face each other symmetrically. Specifically, the molding core 51 includes a trunk portion 53 extending in the vertical direction, and an undercut molding portion 55 having a recess 54 that matches the outer shape of the undercut portion P1 is integrally formed on the upper end side of the trunk portion 53. It is molded into. The same applies to the other molded core 52.

  Of the respective molding cores 51 and 52, the base end side excluding the undercut molding portion 55, that is, the trunk portion 53 has a shape that overlaps in the front-rear direction with the holding piece 40 in between, and the inner surfaces of each other are mutually adjacent. Surface contact is slidable. A concave groove 56 that is slidably fitted to the ridge 41 on the holding piece 40 is provided at a further proximal end (lower end) of the trunk portion 53. Here, the concave groove 56 forms a dovetail by combining two molding cores 51 and 52 together.

  Due to the fitting relationship between the concave groove 56 of each molding core 51, 52 and the protrusion 41 of the holding piece 40, the base end side of each molding core 51, 52 is in the die cutting direction with respect to the holding piece 40. It is slidably connected in both orthogonal directions. Here, each molding core 51, 52 protrudes out of the holder 30 so as to be in contact with each other so as to surround the undercut portion P1 from both sides in the holder 30 and the undercut portion P1. To the mold release positions (see FIG. 2) that are separated from each other.

  As shown in FIGS. 8 and 9, when the molding cores 51 and 52 move from the molding position to the mold release position, the base end side of each of the molding cores 51 and 52 is the other end side from the one end side of the protrusion 41 of the holding piece 40. It is set to pass each other in the opposite direction. That is, in one molding core 51, the concave groove 56 at the base end moves from the left end to the right end on the paper surface, and the other molding core 52 has the concave groove 56 at the base end conversely on the paper surface from the right end to the left end. And in the meantime they cross each other.

  As shown in FIGS. 4 and 5, the molding cores 51 and 52 are shown in FIG. 2 from the molding position shown in FIG. 1 on the inner wall of each piece 30a of the holder 30 when the molded product P is removed. Guide means are provided for guiding along the “inclination direction” that simultaneously moves in the mold release direction and both side directions toward the mold release position. Such guide means are a pair of first oblique grooves 33 and second oblique grooves 34 that are provided on the inner wall of each of the split parts 30a in a concave groove cross section and extend symmetrically to each other. The first oblique groove 33 and the second oblique groove 34 are symmetrical in the left-right direction in the front view of the holder 30 and intersect in an X shape.

  On the other hand, as shown in FIGS. 6 to 9, the outer wall of one of the molded cores 51 and 52 extends in an inclined direction that matches the first oblique groove 33 of the holder 30, and the first A first ridge 57 is slidably fitted into the oblique groove 33 so as to be slidable. The first oblique 57 extends straight from the upper end of the undercut molding portion 55 of the molding core 51 to the lower end of the trunk portion 53. The first oblique 57 may be provided on either the outer wall of the molding core 51 or the inner wall of the holder 30, and the first oblique groove 33 is provided on either one of them.

  Similarly, the outer wall of the other molded core 52 of each of the molded cores 51 and 52 extends in an inclined direction that matches the second oblique groove 34 of the holder 30 and is slidably fitted into the second oblique groove 34. A second oblique line 58 is formed so as to project. The second oblique line 58 extends straight from the upper end of the undercut forming part 55 of the forming core 52 to the lower end of the trunk part 53. The second oblique 58 may be provided on either the outer wall of the molding core 51 or the inner wall of the holder 30, and the second oblique groove 34 is provided on either one of them.

Next, the operation of the present embodiment will be described.
As shown in FIGS. 1 and 3, when the molded product P is molded by the molding die apparatus 10, the mold 11 is arranged so that the lower surface of the fixed mold 12 is aligned with the upper surface of the movable mold 13 of the mold 11. At this time, in the holder 30 provided in the movable mold 13, the respective molding cores 51 and 52 are supported at molding positions in contact with each other so as to surround the undercut portion P <b> 1 of the molded product P from both sides. In such a state, the mold 11 is filled with a molten material and then cooled and solidified to form a molded product P having an undercut portion P1.

  When the molding of the molded product P is completed, the fixed die 12 is detached from the movable die 13, and then the ejector base plate 15 is driven upward as shown in FIG. Then, the ejector pin 20 erected on the ejector base plate 15 protrudes straightly upward in the mold release direction while passing through the vertical hole 13c on the movable mold 13 side. In the holder 30, the holding piece 40 supported by the tip portion 21 of the ejector pin 20 moves together with the ejector pin 20 in the mold release direction.

  As the holding piece 40 moves in the die-cutting direction, the pair of forming cores 51 and 52 whose base ends are connected and supported by the protrusions 41 of the holding piece 40 are respectively shown from the forming positions shown in FIG. It moves to the mold release position shown in No. 2, and the inclination direction which moves simultaneously to a die-cutting direction and a both-sides direction. In other words, the molding cores 51 and 52 are separated from the undercut portion P1 while projecting out of the holder 30.

  In other words, the one molded core 51 is guided along one of the left and right symmetrical inclination directions while the first oblique 57 is sliding in the first oblique groove 33 in the holder 30. At the same time, the other molded core 52 is guided along the other of the inclined directions while the second inclined line 58 slides in the second inclined groove 34 in the holder 30. The first oblique groove 33 and the second oblique groove 34 extend separately in a symmetrical inclination direction.

  As described above, the movement of the molding cores 51 and 52 in the holder 30 is caused by the fitting relationship between the ridges 57 and 58 on the respective outer walls and the oblique grooves 33 and 34 as guide means on the inner wall of the holder 30. By this, it is guided reliably and smoothly in the tilt direction. In addition, since the load at the time of punching out the molded product P is also distributed without being concentrated in one place, the durability is improved. In addition, since high accuracy at the time of design is eased, further cost reduction is possible.

  Further, as shown in FIGS. 8 and 9, the molding cores 51 and 52 are each provided with a shape in which the basic portions 53 overlap each other with the holding piece 40 therebetween, and these basic portions 53 are formed in the holding pieces. 40 is slidably connected to both sides. Then, when the molding cores 51 and 52 move from the molding position to the mold release position, the base ends of the respective core portions 53 are passed back and forth in opposite directions from one end side to the other end side of the holding piece 40. Move to.

  Thereby, although each shaping | molding core 51,52 can be accommodated compactly in the holder 30 in the state which does not spread too much each side, a bigger moving stroke can be ensured at the time of die cutting. Therefore, even if the undercut portion P1 protruding inside the lower surface of the molded product P is greatly uneven on both sides intersecting the die-cutting direction, the undercut portion P1 can be removed without difficulty, and the molded product P The whole can be easily punched.

  Specifically, as shown in FIG. 10, in the molding die device 10 according to the present embodiment, the molding cores 51 and 52 are moved back and forth in the opposite directions from one end side to the other end side of the holding piece 40. Move in a different way. Thereby, the molding cores 51 and 52 are separated from each other up to a large distance L1. On the other hand, as shown in FIG. 11, when the molding cores 51 and 52 move in opposite directions from the center of the holding piece 40 to both ends, the molding cores 51 and 52 are separated from each other by a small distance L2.

  Furthermore, according to the undercut processing mechanism according to the present embodiment, the molding cores 51 and 52 are concentrated only on the movable mold 13 via the holder 30 without being distributed to the ejector base plate 15 and the movable mold 13. Can be arranged. As a result, the molding die apparatus 10 can be configured to be compact as a whole, can meet the demand for space saving, and can be easily processed and assembled into the die 11.

  In particular, as shown in FIG. 6, the undercut processing mechanism can be configured as a unit in which the molding cores 51 and 52 and the holding piece 40 are incorporated in the holder 30 in advance, as shown in FIG. It can be easily retrofitted into the movable mold 13 via the holder 30. Such a configuration is suitable for a case where machining such as making a space for housing the holder 30 in the movable mold 13 itself is easy, as in the case where the movable mold 13 is small.

  In FIG. 2, when the molded product P is removed, as the ejector pin 20 returns to the molding position, it is pulled by the ejector pin 20 and the molding cores 51 and 52 return to the initial position together with the holding piece 40. Further, the fixed mold 12 also returns to the molding position, and the next molded product P is molded. By the way, each shaping | molding core 51 and 52 is designed to the length according to the stroke which can be die-cut of the whole molded article P containing the undercut part P1. Thereby, it can respond | correspond suitably from the big stroke in the die cutting of the molded article P to a small stroke.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to the above-described embodiments, and the present invention can be changed or added without departing from the scope of the present invention. Included in the invention. For example, the shapes of the molded product P and the molding cores 51 and 52 are not limited to those specifically illustrated. Further, instead of assembling the holding piece 40 separately from the ejector pin 20 later, the holding piece 40 may be integrally provided in advance on the tip side of the ejector pin 20.

  Moreover, in the said embodiment, although the undercut shaping | molding part 55 of each shaping | molding core 51,52 is integrally provided in the front end side of each shaping | molding core 51,52, You may attach to the front end side of the shaping | molding cores 51 and 52 so that attachment or detachment is possible separately. Thereby, in order to correspond to various undercut parts P1, it can be changed to another type later and versatility spreads.

  Further, in the above-described embodiment, the holder 30 is integrally provided in the movable mold 13. However, the holder 30 may be integrally provided in the fixed mold 12 instead of the movable mold 13. Further, the holder 30 itself may be configured as a part surrounding the hollow portion 13a in the movable mold 13 (or the fixed mold 12).

  That is, a hollow portion 13a that directly replaces the internal space of the holder 30 is formed directly on the mold 11, and the respective molding cores 51, 52, etc. may be accommodated in the hollow portion 13a. Thereby, the number of parts regarding the holder 30 is reduced, the configuration of the entire molding die apparatus 10 can be further simplified, and the cost can be reduced.

  Since it can be configured compactly and can meet the demand for space saving, it is excellent in processing and assembling into small molds. The present invention can be applied when the shape is uneven on both the left and right sides intersecting the direction.

P ... Molded product P1 ... Undercut part 10 ... Molding die device 11 ... Mold 12 ... Fixed mold 13 ... Movable mold 13a ... Hollow part 13b ... Lower plate 13c ... Vertical hole 13d ... Block 14 ... Moving mounting plate 15 ... Ejector base plate 20 ... Ejector pin 21 ... Tip end portion 22 ... Base end portion 23 ... Knock pin 30 ... Holder 30a ... One-piece parts 33 ... First oblique groove 34 ... Second oblique groove 40 ... Holding piece 41 ... Projection 51 ... Molding 51 Core 52 ... Molding core 53 ... Core portion 54 ... Recessed portion 55 ... Undercut molding portion 56 ... Ditch groove 57 ... First oblique line 58 ... Second oblique line

Claims (6)

In an undercut processing mechanism that molds a molded product having an undercut portion with a fixed die and a movable die, and makes the undercut portion ready for die cutting,
A single holder installed in the fixed mold or the movable mold;
A pair of molded cores that are housed in the holder and molded in a state of surrounding the undercut portion from both sides intersecting the die cutting direction;
A holding piece housed in the holder and movable in a die-cutting direction;
Each of the molded cores is slidably connected to both sides of the holding piece with respect to the holding piece so as to cross the die-cutting direction and escape from the undercut part, and the undercut part is inserted in the holder. It is possible to move to a molding position that contacts each other so as to surround from both sides, and a mold release position that protrudes out of the holder and separates from the undercut part,
A pair of symmetrically extending guides along the inclined direction in which the molding core moves from the molding position to the mold release position and simultaneously moves in the die-cutting direction and both side directions in accordance with the movement of the holding piece in the holder. Providing a guide means,
Each of the molding cores is provided so that at least the base end side overlaps the front and rear with the holding piece in between, and when moving from the molding position to the mold release position, the base end side is different from the one end side of the holding piece. Undercut treatment mechanism characterized by passing back and forth in opposite directions to the end side. A first slant extending in the inclined direction in which the one molded core moves to one of the outer wall of one of the molded cores and the inner wall of the holder in sliding contact with the outer wall of the one molded core. A groove is provided, and on the other side, a first oblique line that extends in the inclined direction and is slidably fitted into the first oblique groove is provided, and the first oblique groove or the first oblique line in the holder is provided. As one of the guide means,
A second slant extending in the inclined direction in which the other molded core moves to either one of the outer wall of the other molded core and the inner wall of the holder in sliding contact with the outer wall of the other molded core. A groove is provided, and a second oblique line that extends in the inclined direction and is slidably fitted into the second oblique groove is provided on either one of the grooves, and the second oblique groove or the second oblique line in the holder is provided. 2. The undercut processing mechanism according to claim 1, wherein the undercut processing mechanism is the other of the guide means. It has an ejector pin that is driven in the die-cutting direction and protrudes,
3. The undercut processing mechanism according to claim 1, wherein the ejector pin is disposed at a position where a tip side thereof faces the inside of the holder, and the tip side is integrally connected to the holding piece.   4. The undercut processing mechanism according to claim 1, wherein a tip end side for molding the undercut portion of each molded core is detachably assembled as a separate body. 5.   The undercut processing mechanism according to claim 1, 2, 3, or 4, wherein each of the molding cores is set to a length corresponding to a die cutting stroke of the molded product.   The under holder according to claim 1, 2, 3, 4 or 5, wherein the holder is configured as a part of a mold itself surrounding a hollow portion provided in the movable mold or the fixed mold provided with the holder. Cut processing mechanism.

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